Changes between Initial Version and Version 1 of DescribeHook

Timestamp:

03/18/08 07:16:38 (5 years ago)

Author:

anonymous

Comment:

--

DescribeHook

@@ +1 @@
+= What is a hook? =
+
+A hook in [wiki:CLFSWM] is a function, a symbol, a list of functions or a list of symbols.
+
+A function is called as is with parameters passed from call-hook.
+
+A symbol function is called like a function.
+
+If the hook is a list then functions or symbols are called in order.
+
+Call-hook return the result of the last function executed in the hook.
+
+For example:
+
+{{{
+(defun fun-1 (x y) (print (list 'fun-1 x y)))
+(defun fun-2 (x y) (print (list 'fun-2 x y)))
+(defun fun-3 (x y) (print (list 'fun-3 x y)))
+
+(defvar *hook* #'fun-1)
+(call-hook *hook* 10 20)
+=> (FUN-1 10 20)
+
+(setf *hook* 'fun-2)
+(call-hook *hook* 10 30)
+=> (FUN-2 10 30)
+
+(setf *hook* (list 'fun-1 'fun-2 'fun-3))
+(call-hook *hook* 10 "foo")
+=> (FUN-1 10 "foo")
+   (FUN-2 10 "foo")
+   (FUN-3 10 "foo")
+
+(setf *hook* (list #'fun-1 #'fun-2 #'fun-3))
+(call-hook *hook* 10 "foo")
+=> (FUN-1 10 "foo")
+   (FUN-2 10 "foo")
+   (FUN-3 10 "foo")
+}}}